8079e29c14fd4ca1212bea28ac313b523a67b5d3
[linux-3.10.git] / include / asm-x86_64 / uaccess.h
1 #ifndef __X86_64_UACCESS_H
2 #define __X86_64_UACCESS_H
3
4 /*
5  * User space memory access functions
6  */
7 #include <linux/compiler.h>
8 #include <linux/errno.h>
9 #include <linux/prefetch.h>
10 #include <asm/page.h>
11
12 #define VERIFY_READ 0
13 #define VERIFY_WRITE 1
14
15 /*
16  * The fs value determines whether argument validity checking should be
17  * performed or not.  If get_fs() == USER_DS, checking is performed, with
18  * get_fs() == KERNEL_DS, checking is bypassed.
19  *
20  * For historical reasons, these macros are grossly misnamed.
21  */
22
23 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
24
25 #define KERNEL_DS       MAKE_MM_SEG(0xFFFFFFFFFFFFFFFFUL)
26 #define USER_DS         MAKE_MM_SEG(PAGE_OFFSET)
27
28 #define get_ds()        (KERNEL_DS)
29 #define get_fs()        (current_thread_info()->addr_limit)
30 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
31
32 #define segment_eq(a,b) ((a).seg == (b).seg)
33
34 #define __addr_ok(addr) (!((unsigned long)(addr) & (current_thread_info()->addr_limit.seg)))
35
36 /*
37  * Uhhuh, this needs 65-bit arithmetic. We have a carry..
38  */
39 #define __range_not_ok(addr,size) ({ \
40         unsigned long flag,roksum; \
41         __chk_user_ptr(addr); \
42         asm("# range_ok\n\r" \
43                 "addq %3,%1 ; sbbq %0,%0 ; cmpq %1,%4 ; sbbq $0,%0"  \
44                 :"=&r" (flag), "=r" (roksum) \
45                 :"1" (addr),"g" ((long)(size)),"g" (current_thread_info()->addr_limit.seg)); \
46         flag; })
47
48 #define access_ok(type, addr, size) (__range_not_ok(addr,size) == 0)
49
50 /*
51  * The exception table consists of pairs of addresses: the first is the
52  * address of an instruction that is allowed to fault, and the second is
53  * the address at which the program should continue.  No registers are
54  * modified, so it is entirely up to the continuation code to figure out
55  * what to do.
56  *
57  * All the routines below use bits of fixup code that are out of line
58  * with the main instruction path.  This means when everything is well,
59  * we don't even have to jump over them.  Further, they do not intrude
60  * on our cache or tlb entries.
61  */
62
63 struct exception_table_entry
64 {
65         unsigned long insn, fixup;
66 };
67
68 #define ARCH_HAS_SEARCH_EXTABLE
69
70 /*
71  * These are the main single-value transfer routines.  They automatically
72  * use the right size if we just have the right pointer type.
73  *
74  * This gets kind of ugly. We want to return _two_ values in "get_user()"
75  * and yet we don't want to do any pointers, because that is too much
76  * of a performance impact. Thus we have a few rather ugly macros here,
77  * and hide all the ugliness from the user.
78  *
79  * The "__xxx" versions of the user access functions are versions that
80  * do not verify the address space, that must have been done previously
81  * with a separate "access_ok()" call (this is used when we do multiple
82  * accesses to the same area of user memory).
83  */
84
85 #define __get_user_x(size,ret,x,ptr) \
86         asm volatile("call __get_user_" #size \
87                 :"=a" (ret),"=d" (x) \
88                 :"c" (ptr) \
89                 :"r8")
90
91 /* Careful: we have to cast the result to the type of the pointer for sign reasons */
92 #define get_user(x,ptr)                                                 \
93 ({      unsigned long __val_gu;                                         \
94         int __ret_gu;                                                   \
95         __chk_user_ptr(ptr);                                            \
96         switch(sizeof (*(ptr))) {                                       \
97         case 1:  __get_user_x(1,__ret_gu,__val_gu,ptr); break;          \
98         case 2:  __get_user_x(2,__ret_gu,__val_gu,ptr); break;          \
99         case 4:  __get_user_x(4,__ret_gu,__val_gu,ptr); break;          \
100         case 8:  __get_user_x(8,__ret_gu,__val_gu,ptr); break;          \
101         default: __get_user_bad(); break;                               \
102         }                                                               \
103         (x) = (typeof(*(ptr)))__val_gu;                         \
104         __ret_gu;                                                       \
105 })
106
107 extern void __put_user_1(void);
108 extern void __put_user_2(void);
109 extern void __put_user_4(void);
110 extern void __put_user_8(void);
111 extern void __put_user_bad(void);
112
113 #define __put_user_x(size,ret,x,ptr)                                    \
114         asm volatile("call __put_user_" #size                   \
115                 :"=a" (ret)                                             \
116                 :"c" (ptr),"d" (x)                                      \
117                 :"r8")
118
119 #define put_user(x,ptr)                                                 \
120   __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
121
122 #define __get_user(x,ptr) \
123   __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
124 #define __put_user(x,ptr) \
125   __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
126
127 #define __get_user_unaligned __get_user
128 #define __put_user_unaligned __put_user
129
130 #define __put_user_nocheck(x,ptr,size)                  \
131 ({                                                      \
132         int __pu_err;                                   \
133         __put_user_size((x),(ptr),(size),__pu_err);     \
134         __pu_err;                                       \
135 })
136
137
138 #define __put_user_check(x,ptr,size)                    \
139 ({                                                      \
140         int __pu_err;                                   \
141         typeof(*(ptr)) __user *__pu_addr = (ptr);       \
142         switch (size) {                                 \
143         case 1: __put_user_x(1,__pu_err,x,__pu_addr); break;    \
144         case 2: __put_user_x(2,__pu_err,x,__pu_addr); break;    \
145         case 4: __put_user_x(4,__pu_err,x,__pu_addr); break;    \
146         case 8: __put_user_x(8,__pu_err,x,__pu_addr); break;    \
147         default: __put_user_bad();                      \
148         }                                               \
149         __pu_err;                                       \
150 })
151
152 #define __put_user_size(x,ptr,size,retval)                              \
153 do {                                                                    \
154         retval = 0;                                                     \
155         __chk_user_ptr(ptr);                                            \
156         switch (size) {                                                 \
157           case 1: __put_user_asm(x,ptr,retval,"b","b","iq",-EFAULT); break;\
158           case 2: __put_user_asm(x,ptr,retval,"w","w","ir",-EFAULT); break;\
159           case 4: __put_user_asm(x,ptr,retval,"l","k","ir",-EFAULT); break;\
160           case 8: __put_user_asm(x,ptr,retval,"q","","Zr",-EFAULT); break;\
161           default: __put_user_bad();                                    \
162         }                                                               \
163 } while (0)
164
165 /* FIXME: this hack is definitely wrong -AK */
166 struct __large_struct { unsigned long buf[100]; };
167 #define __m(x) (*(struct __large_struct __user *)(x))
168
169 /*
170  * Tell gcc we read from memory instead of writing: this is because
171  * we do not write to any memory gcc knows about, so there are no
172  * aliasing issues.
173  */
174 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errno)        \
175         asm volatile(                                   \
176                 "1:     mov"itype" %"rtype"1,%2\n"              \
177                 "2:\n"                                          \
178                 ".section .fixup,\"ax\"\n"                      \
179                 "3:     mov %3,%0\n"                            \
180                 "       jmp 2b\n"                               \
181                 ".previous\n"                                   \
182                 ".section __ex_table,\"a\"\n"                   \
183                 "       .align 8\n"                             \
184                 "       .quad 1b,3b\n"                          \
185                 ".previous"                                     \
186                 : "=r"(err)                                     \
187                 : ltype (x), "m"(__m(addr)), "i"(errno), "0"(err))
188
189
190 #define __get_user_nocheck(x,ptr,size)                          \
191 ({                                                              \
192         int __gu_err;                                           \
193         unsigned long __gu_val;                                 \
194         __get_user_size(__gu_val,(ptr),(size),__gu_err);        \
195         (x) = (typeof(*(ptr)))__gu_val;                 \
196         __gu_err;                                               \
197 })
198
199 extern int __get_user_1(void);
200 extern int __get_user_2(void);
201 extern int __get_user_4(void);
202 extern int __get_user_8(void);
203 extern int __get_user_bad(void);
204
205 #define __get_user_size(x,ptr,size,retval)                              \
206 do {                                                                    \
207         retval = 0;                                                     \
208         __chk_user_ptr(ptr);                                            \
209         switch (size) {                                                 \
210           case 1: __get_user_asm(x,ptr,retval,"b","b","=q",-EFAULT); break;\
211           case 2: __get_user_asm(x,ptr,retval,"w","w","=r",-EFAULT); break;\
212           case 4: __get_user_asm(x,ptr,retval,"l","k","=r",-EFAULT); break;\
213           case 8: __get_user_asm(x,ptr,retval,"q","","=r",-EFAULT); break;\
214           default: (x) = __get_user_bad();                              \
215         }                                                               \
216 } while (0)
217
218 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errno)        \
219         asm volatile(                                   \
220                 "1:     mov"itype" %2,%"rtype"1\n"              \
221                 "2:\n"                                          \
222                 ".section .fixup,\"ax\"\n"                      \
223                 "3:     mov %3,%0\n"                            \
224                 "       xor"itype" %"rtype"1,%"rtype"1\n"       \
225                 "       jmp 2b\n"                               \
226                 ".previous\n"                                   \
227                 ".section __ex_table,\"a\"\n"                   \
228                 "       .align 8\n"                             \
229                 "       .quad 1b,3b\n"                          \
230                 ".previous"                                     \
231                 : "=r"(err), ltype (x)                          \
232                 : "m"(__m(addr)), "i"(errno), "0"(err))
233
234 /*
235  * Copy To/From Userspace
236  */
237
238 /* Handles exceptions in both to and from, but doesn't do access_ok */
239 __must_check unsigned long
240 copy_user_generic(void *to, const void *from, unsigned len);
241
242 __must_check unsigned long
243 copy_to_user(void __user *to, const void *from, unsigned len);
244 __must_check unsigned long
245 copy_from_user(void *to, const void __user *from, unsigned len);
246 __must_check unsigned long
247 copy_in_user(void __user *to, const void __user *from, unsigned len);
248
249 static __always_inline __must_check
250 int __copy_from_user(void *dst, const void __user *src, unsigned size)
251
252         int ret = 0;
253         if (!__builtin_constant_p(size))
254                 return copy_user_generic(dst,(__force void *)src,size);
255         switch (size) { 
256         case 1:__get_user_asm(*(u8*)dst,(u8 __user *)src,ret,"b","b","=q",1); 
257                 return ret;
258         case 2:__get_user_asm(*(u16*)dst,(u16 __user *)src,ret,"w","w","=r",2);
259                 return ret;
260         case 4:__get_user_asm(*(u32*)dst,(u32 __user *)src,ret,"l","k","=r",4);
261                 return ret;
262         case 8:__get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",8);
263                 return ret; 
264         case 10:
265                 __get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",16);
266                 if (unlikely(ret)) return ret;
267                 __get_user_asm(*(u16*)(8+(char*)dst),(u16 __user *)(8+(char __user *)src),ret,"w","w","=r",2);
268                 return ret; 
269         case 16:
270                 __get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",16);
271                 if (unlikely(ret)) return ret;
272                 __get_user_asm(*(u64*)(8+(char*)dst),(u64 __user *)(8+(char __user *)src),ret,"q","","=r",8);
273                 return ret; 
274         default:
275                 return copy_user_generic(dst,(__force void *)src,size); 
276         }
277 }       
278
279 static __always_inline __must_check
280 int __copy_to_user(void __user *dst, const void *src, unsigned size)
281
282         int ret = 0;
283         if (!__builtin_constant_p(size))
284                 return copy_user_generic((__force void *)dst,src,size);
285         switch (size) { 
286         case 1:__put_user_asm(*(u8*)src,(u8 __user *)dst,ret,"b","b","iq",1); 
287                 return ret;
288         case 2:__put_user_asm(*(u16*)src,(u16 __user *)dst,ret,"w","w","ir",2);
289                 return ret;
290         case 4:__put_user_asm(*(u32*)src,(u32 __user *)dst,ret,"l","k","ir",4);
291                 return ret;
292         case 8:__put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",8);
293                 return ret; 
294         case 10:
295                 __put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",10);
296                 if (unlikely(ret)) return ret;
297                 asm("":::"memory");
298                 __put_user_asm(4[(u16*)src],4+(u16 __user *)dst,ret,"w","w","ir",2);
299                 return ret; 
300         case 16:
301                 __put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",16);
302                 if (unlikely(ret)) return ret;
303                 asm("":::"memory");
304                 __put_user_asm(1[(u64*)src],1+(u64 __user *)dst,ret,"q","","ir",8);
305                 return ret; 
306         default:
307                 return copy_user_generic((__force void *)dst,src,size); 
308         }
309 }       
310
311 static __always_inline __must_check
312 int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
313
314         int ret = 0;
315         if (!__builtin_constant_p(size))
316                 return copy_user_generic((__force void *)dst,(__force void *)src,size);
317         switch (size) { 
318         case 1: { 
319                 u8 tmp;
320                 __get_user_asm(tmp,(u8 __user *)src,ret,"b","b","=q",1); 
321                 if (likely(!ret))
322                         __put_user_asm(tmp,(u8 __user *)dst,ret,"b","b","iq",1); 
323                 return ret;
324         }
325         case 2: { 
326                 u16 tmp;
327                 __get_user_asm(tmp,(u16 __user *)src,ret,"w","w","=r",2); 
328                 if (likely(!ret))
329                         __put_user_asm(tmp,(u16 __user *)dst,ret,"w","w","ir",2); 
330                 return ret;
331         }
332
333         case 4: { 
334                 u32 tmp;
335                 __get_user_asm(tmp,(u32 __user *)src,ret,"l","k","=r",4); 
336                 if (likely(!ret))
337                         __put_user_asm(tmp,(u32 __user *)dst,ret,"l","k","ir",4); 
338                 return ret;
339         }
340         case 8: { 
341                 u64 tmp;
342                 __get_user_asm(tmp,(u64 __user *)src,ret,"q","","=r",8); 
343                 if (likely(!ret))
344                         __put_user_asm(tmp,(u64 __user *)dst,ret,"q","","ir",8); 
345                 return ret;
346         }
347         default:
348                 return copy_user_generic((__force void *)dst,(__force void *)src,size); 
349         }
350 }       
351
352 __must_check long 
353 strncpy_from_user(char *dst, const char __user *src, long count);
354 __must_check long 
355 __strncpy_from_user(char *dst, const char __user *src, long count);
356 __must_check long strnlen_user(const char __user *str, long n);
357 __must_check long __strnlen_user(const char __user *str, long n);
358 __must_check long strlen_user(const char __user *str);
359 __must_check unsigned long clear_user(void __user *mem, unsigned long len);
360 __must_check unsigned long __clear_user(void __user *mem, unsigned long len);
361
362 __must_check long __copy_from_user_inatomic(void *dst, const void __user *src, unsigned size);
363
364 static __must_check __always_inline int
365 __copy_to_user_inatomic(void __user *dst, const void *src, unsigned size)
366 {
367         return copy_user_generic((__force void *)dst, src, size);
368 }
369
370 #endif /* __X86_64_UACCESS_H */